Photostability of quantum dot micelles under ultraviolet irradiation.

Phospholipid quantum dot micelles are useful for bio-applications because of their amphiphilicity and exceptional biocompatibilities. We investigated the uptake of phospholipid [polyethylene glycol (PEG), biotin, and folic acid terminated] modified CdSe/ZnS quantum dot micelles by cancer cells and its photostability under ultrviolet light in the C spectrum (UV-C) (254 nm) or UV-A (365 nm) light irradiation. The stability of micelles to the exposure of UV-C and UV-A light was assessed. Biotin-modified quantum dot micelles give photoluminescence enhancement under UV-C light irradiation. Folate modified micelle under UV-C and UV-A results show considerable photoluminescence enhancement. Photoluminescence lifetime measurements showed 7.04, 8.11 and 11.42 ns for PEG, folate, and biotin terminated phospholipid micelles, respectively. Folate and biotin-modified quantum dot micelles showed excellent uptake by HeLa cells under fluorescence confocal microscopy. Phospholipid CdSe/ZnS quantum dot micelles can be potentially used for diagnosis and treatment of cancer in the future.